Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| association of rumination time and health status with milk yield and composition in early-lactation dairy cows. | the objective of this study was to determine the associations of rumination time (rt) and health status with milk yield and milk composition. this study used 339 dairy cows from 4 commercial dairy farms in ontario, canada (first lactation, n = 107; second lactation, n = 112; ≥third lactation, n = 120). rumination time was monitored (24 h/d) using an automated system from 1 to 28 d in milk (dim). cows were milked 3×/d on each farm, and 2 farms recorded milk weights at each milking to determine da ... | 2018 | 29055534 |
| short communication: prevalence of digital dermatitis in canadian dairy cattle classified as high, average, or low antibody- and cell-mediated immune responders. | lameness is a major animal welfare issue affecting canadian dairy producers, and it can lead to production, reproduction, and health problems in dairy cattle herds. although several different lesions affect dairy cattle hooves, studies show that digital dermatitis is the most common lesion identified in canadian dairy herds. it has also been shown that dairy cattle classified as having high immune response (ir) have lower incidence of disease compared with those animals with average and low ir; ... | 2017 | 28780089 |
| estimated antimicrobial dispensing frequency and preferences for lactating cow therapy by ontario dairy veterinarians. | in this cross-sectional study, data were collected from responses to a questionnaire on dispensing frequencies of antimicrobials used by dairy practitioners in ontario in dairy cattle in 2001. data were validated through clinical case scenarios. respondents reported using antimicrobials across all categories of importance to human medicine (medically important, categories i to iii) with a diversity of treatment combinations and routes of administration. respondents anticipated that a request for ... | 2017 | 28042151 |
| investigating the within-herd prevalence and risk factors for ketosis in dairy cattle in ontario as diagnosed by the test-day concentration of β-hydroxybutyrate in milk. | an observational study of 790 to over 3,000 herds was conducted to estimate the within-herd prevalence and cow-level risk factors for ketosis in dairy cattle in herds that participate in a dairy herd improvement association (dhia) program. ketosis or hyperketolactia (ket) was diagnosed as milk β-hydroxybutyrate ≥0.15 mmol/l at first dhia test when tested within the first 30 d in milk. seven hundred ninety-five herds providing at least 61 first milk tests from june 2014 to december 2015 were used ... | 2017 | 28012623 |
| molecular and statistical analysis of campylobacter spp. and antimicrobial-resistant campylobacter carriage in wildlife and livestock from ontario farms. | the objectives of this study were to (i) compare the carriage of campylobacter and antimicrobial-resistant campylobacter among livestock and mammalian wildlife on ontario farms, and (ii) investigate the potential sharing of campylobacter subtypes between livestock and wildlife. using data collected from a cross-sectional study of 25 farms in 2010, we assessed associations, using mixed logistic regression models, between campylobacter and antimicrobial-resistant campylobacter carriage and the fol ... | 2017 | 27460061 |
| associations between lying behavior and lameness in canadian holstein-friesian cows housed in freestall barns. | lying behavior is an important measure of comfort and well-being in dairy cattle, and changes in lying behavior are potential indicators and predictors of lameness. our objectives were to determine individual and herd-level risk factors associated with measures of lying behavior, and to evaluate whether automated measures of lying behavior can be used to detect lameness. a purposive sample of 40 holstein cows was selected from each of 141 dairy farms in alberta, ontario, and québec. lying behavi ... | 2016 | 26805982 |
| mapping rural community and dairy cow heat stress in southern ontario: a common geographic pattern from 2010 to 2012. | climate change has increased the occurrence of heat waves, causing heat stress among humans and livestock, with potentially fatal consequences. heat stress maps provide information about related health risks and insight for control strategies. weather data were collected throughout southern ontario, and the heat stress index (hsi) was estimated for 2010-2012. geostatistical kriging was applied to map heat stress, heat waves, and control periods. average hsi for each period ranged from 55 to 78 d ... | 2016 | 26067385 |
| calving management practices on canadian dairy farms: prevalence of practices. | little information is available about current practices around calving in dairy cattle. the aim of this study was to describe calving management practices in the canadian dairy industry related to housing, calving protocols, monitoring of parturition, and calving assistance. information was gathered by in-person interviews from 236 dairy farms from 3 canadian provinces (alberta, ontario, and québec) with freestalls and an automatic milking system (n=24), freestalls with a parlor (n=112), and tie ... | 2016 | 26723128 |
| incidence rate of pathogen-specific clinical mastitis on conventional and organic canadian dairy farms. | mastitis is a common and costly production disease on dairy farms. in canada, the incidence rate of clinical mastitis (ircm) has been determined for conventionally managed dairy farms; however, no studies to date have assessed rates in organically managed systems. the objectives of this observational study were (1) to determine the producer-reported ircm and predominant pathogen types on conventional and organic dairy farms in southern ontario, canada, and (2) to evaluate the association of both ... | 2016 | 26686728 |
| studying the relationship between on-farm environmental conditions and local meteorological station data during the summer. | high ambient heat and humidity have profound effects on the production, health, profitability, and welfare of dairy cattle. to describe the relationship between summer temperature and relative humidity in the barn and determine the appropriateness of using meteorological station data as a surrogate for on-farm environmental monitoring, a study was conducted on 48 farms in ontario, canada, over the summer (may through september) of 2013. within-barn environmental conditions were recorded using re ... | 2016 | 26778304 |
| lying times of lactating cows on dairy farms with automatic milking systems and the relation to lameness, leg lesions, and body condition score. | lying down and resting are important for optimal cow health, welfare, and production. in comparison with free stall farms with a milking parlor, farms with automated milking systems (ams) may place less constraint on how long cows can lie down. however, few studies report lying times on ams farms. the aims of this study were to describe the variation in lying times of dairy cows in ams farms and to understand how much of the variation in individual lying times is related to cow-level factors, in ... | 2016 | 26547637 |
| an assessment tool to help producers improve cow comfort on their farms. | effective management and an appropriate environment are essential for dairy cattle health and welfare. codes of practice provide dairy producers with best practice guidance for the care and handling of their cattle. new canadian recommendations have been established for the dairy industry. the objectives of this study were to develop an on-farm assessment tool that helps producers assess how well they are meeting their code of practice and that identifies management and environment modifications ... | 2015 | 25465625 |
| heat stress related dairy cow mortality during heat waves and control periods in rural southern ontario from 2010-2012. | heat stress is a physiological response to extreme environmental heat such as heat waves. heat stress can result in mortality in dairy cows when extreme heat is both rapidly changing and has a long duration. as a result of climate change, heat waves, which are defined as 3 days of temperatures of 32 °c or above, are an increasingly frequent extreme weather phenomenon in southern ontario. heat waves are increasing the risk for on-farm dairy cow mortality in southern ontario. heat stress indices ( ... | 2015 | 26610334 |
| antimicrobial dispensing by ontario dairy veterinarians. | this questionnaire-based cross-sectional study was designed to capture the demographics of dairy practitioners in ontario and to describe aspects of antimicrobial dispensing on-farm and over-the-counter by these veterinarians. the information collected revealed that the prescription status of a drug and the level of veterinary-client-patient relationship were important elements of dispensing policies. over-the-counter dispensing records were incomplete, while only a small proportion of on-farm d ... | 2015 | 26130834 |
| comparing elisa test-positive prevalence, risk factors and management recommendations for johne's disease prevention between organic and conventional dairy farms in ontario, canada. | johne's disease (jd) is a chronic, infectious disease in cattle. between 2010 and 2013, a voluntary jd control program was successfully launched in ontario, canada, including a risk assessment and management plan (ramp) and jd elisa testing of the entire milking herd. over the last decade, the organic dairy sector has been growing. however, organic farming regulations and philosophies may influence the risk for jd transmission on ontario organic dairy farms. the aim of this cross-sectional study ... | 2015 | 26454797 |
| prevalence of lameness and associated risk factors in canadian holstein-friesian cows housed in freestall barns. | lameness is a severe welfare problem and a production-limiting disease in dairy farming. the objectives of this study were to determine prevalence of lameness and investigate cow- and herd-level factors associated with lameness in dairy cows housed in freestall barns in 3 canadian provinces. a purposive sample of 40 holstein-friesian cows was selected from each of 141 dairy farms in québec, ontario, and alberta. in total, 5,637 cows were scored once for lameness (presence of limping when walking ... | 2015 | 26254526 |
| ketonemia in dairy goats: effect of dry period length and effect on lying behavior. | in dairy animals, a successful transition from one lactation to the next includes minimizing negative energy balance. cows experiencing excessive negative energy balance typically develop metabolic complications following parturition (e.g., ketosis); does are also susceptible before kidding (e.g., pregnancy toxemia). it is not known to what extent the provision and the length of the dry period affect these conditions in does. furthermore, whereas clinical symptoms of these conditions include let ... | 2015 | 26117354 |
| relationship between postmilking standing duration and risk of intramammary infection in freestall-housed dairy cows milked 3 times per day. | recent evidence exists to suggest that the risk of subclinical mastitis, particularly those infections caused by environmental pathogens, in dairy cows is related to standing and lying patterns. the objective of this study was to determine the association between postmilking standing duration (pmsd) of dairy cows milked 3×/d and risk of intramammary infection (imi). four commercial freestall dairy herds in eastern ontario, milking 3×/d, were enrolled in a longitudinal study. forty holstein-fries ... | 2014 | 24679939 |
| prevalence of and factors associated with hock, knee, and neck injuries on dairy cows in freestall housing in canada. | injuries are a widespread problem in the dairy industry. the objective of this study was to determine the prevalence of and explore the animal-based and environmental factors associated with hock, knee, and neck injuries on dairy cows in freestall housing in ontario and alberta, canada. freestall dairy farms in the provinces of ontario (n=40) and alberta (n=50) were visited for cross-sectional data collection. a purposive sample of 40 lactating holstein cows was selected for detailed observation ... | 2014 | 24359942 |
| a national investigation of the prevalence and diversity of thermophilic campylobacter species in agricultural watersheds in canada. | the occurrence and diversity of thermophilic campylobacter species (c. jejuni, coli, and lari) were studied in water samples from four river basins located across canada. these basins located in quebec (bras d'henri), alberta (oldman), ontario (south nation), and british columbia (sumas) represented some of the most intensive farming areas in canada for hog, beef cattle, dairy cattle, and poultry, respectively. this study analyzed 769 water samples collected from 23 monitoring sites with agricul ... | 2014 | 24930011 |
| prevalence of antibodies to leptospira in wild mammals trapped on livestock farms in ontario, canada. | to determine the prevalence and diversity of leptospira serogroups circulating in wildlife on farms in ontario, we tested samples from 51 raccoons (procyon lotor), seven skunks (mephitis mephitis), four rats (rattus norvegicus), and three opossums (didelphis virginiana) that were trapped on 27 livestock (swine [sus scrofa], cattle [bos taurus]) farms in 2010. seventeen of 51 raccoons (33%; 95% confidence interval [ci], 21-48%) sampled were positive for at least one leptospira serogroup using the ... | 2014 | 24807356 |
| effect of prepartum administration of recombinant bovine somatotropin on health and performance of lactating dairy cows. | a double-blind, randomized clinical trial was conducted in 5 commercial dairy herds in southern ontario with 1,362 cows enrolled to evaluate the effect of prepartum administration of recombinant bovine somatotropin (rbst) on health and performance. cows were randomly assigned to receive either 325 mg of sometribove zinc suspension (n=680) or a placebo injection (n=682; control) subcutaneously every 14 d until calving. treatments started 28 to 22 d before expected calving, with a maximum of 3 tre ... | 2014 | 25087023 |
| factors associated with morbidity, mortality, and growth of dairy heifer calves up to 3 months of age. | calfhood disease is an important problem on many dairy operations that can have substantial effects on heifer survival and productivity, and has economic and welfare impacts. neonatal calf diarrhea (ncd) and bovine respiratory disease (brd) are the most common causes of morbidity and mortality in young dairy cattle. the objective of this observational study was to investigate factors associated with the risks of morbidity and mortality, and with growth, in commercial dairy heifers calves. a tota ... | 2014 | 24269039 |
| associations of herd- and cow-level factors, cow lying behavior, and risk of elevated somatic cell count in free-stall housed lactating dairy cows. | recent evidence suggests that the risk of intramammary infection in dairy cows is related to lying patterns. the objectives of this study were to quantify the standing and lying behavior of dairy cows milked 3×/d, determine the cow- and herd-level factors associated with these behaviors, and relate these findings to the risk of an elevated somatic cell count (scc). five commercial free-stall dairy herds in eastern ontario, milking 3×/d, were enrolled in a longitudinal study. forty holstein-fries ... | 2013 | 23791124 |
| short communication: analysis of health and survival in a population of ontario holstein heifer calves. | the objective of the present study was to investigate health and survival in heifer calves, from 16 farms in southwestern ontario. research technicians visited the farms on a weekly schedule for 16 mo, starting in january 2008, and collected blood samples and various measurements to determine the overall health status of the calves. data of 1,588 holstein heifer calves from birth until 90 to 120 d of age were analyzed. initially, a survival analysis was carried out to determine which factors sur ... | 2013 | 23438685 |
| genetic parameters for hoof lesions and their relationship with feet and leg traits in canadian holstein cows. | the objectives were (1) to estimate the genetic parameters and breeding values of hoof lesions, (2) to estimate the phenotypic effect of each feet and legs conformation traits on hoof lesions, and (3) to estimate genetic correlations between hoof lesions with feet and legs conformation traits. the presence or absence of specific hoof lesions was recorded for each hoof. lesions were classified into infectious (digital and interdigital dermatitis, foot rot, and heel erosion), horn (sole and toe ul ... | 2013 | 23415531 |
| evaluation of enzyme-linked immunosorbent assays performed on milk and serum samples for detection of neosporosis and leukosis in lactating dairy cows. | serum and milk samples from 1229 cows on 22 ontario dairy farms were individually tested for antibodies specific for bovine leukosis virus (blv) and neospora caninum by enzyme-linked immunosorbent assay (elisa). antibodies against blv were present in 361 serum samples (29.4%) and 369 milk samples (30.0%). comparing the 2 tests, agreement was almost perfect (k = 0.86; 95% ci = 0.83 to 0.90) and the proportions of samples positive were not significantly different (p = 0.56). both tests identified ... | 2013 | 24082160 |
| Short communication: Bulk milk somatic cell penalties in herds enrolled in Dairy Herd Improvement programs. | The objective of this study was to determine the effect of somatic cell count (SCC) monitoring at the cow level through Dairy Herd Improvement (DHI) programs on the risk of bulk tank SCC (BTSCC) penalties. For the year 2009, BTSCC for all producers in Ontario were examined, for a total of 2,898 DHI herds, 1,186 non-DHI herds, and 48,250 BTSCC records. Two penalty levels were examined, where BTSCC exceeded 499,000 (P500) and 399,000 (P400) cells/mL. Data were modeled first to determine the odds o ... | 2012 | 22192202 |
| herd characteristics and cow-level factors associated with prototheca mastitis on dairy farms in ontario, canada. | prototheca spp. are algae that cause incurable acute or chronic mastitis in dairy cows. the aim of this case-control study was the identification of cow- and herd-level risk factors for this unusual mastitis pathogen. aseptically collected composite milk samples from 2,428 milking cows in 23 case and 23 control herds were collected between january and may 2011. a questionnaire was administered to the producers, and cow-level production and demographic data were gathered. in 58 of 64 isolates, pr ... | 2012 | 22884347 |
| associations between paratuberculosis milk elisa result, milk production, and breed in canadian dairy cows. | the 3 objectives of this study were (1) to quantify milk production differences among cows with different paratuberculosis (paratb) milk elisa results; (2) to determine if production differences existed in lactations preceding the test among cows with different paratb milk elisa results; and (3) to assess whether channel island breeds were more likely to test positive with the paratb milk elisa than other dairy breeds. current and completed lactation records from 35,591 dairy cows in ontario and ... | 2011 | 21257043 |
| estimating potential epidemic size following introduction of a long-incubation disease in scale-free connected networks of milking-cow movements in ontario, canada. | we used the movements of adult milking cows among farms enrolled in the dairy herd improvement (dhi) program in ontario to explore the size of an epidemic that might result from farm-to-farm movements of cows in the province if a reportable long-incubation infection like tuberculosis (tb) were introduced and not detected for 1-3 years after introduction. a directed network was created for each year (2004-2006) using all pairs of individual shipments, defined as the movement of one or more cows o ... | 2011 | 21388696 |
| bovine pglyrp1 polymorphisms and their association with resistance to mycobacterium avium ssp. paratuberculosis. | mycobacterium avium ssp. paratuberculosis (map) causes a chronic, granulomatous inflammatory condition of the intestines in ruminants and wild-type species. it causes significant economic losses to the dairy and beef industries owing to reduced productivity, premature culling and mortality. bovine peptidoglycan recognition protein 1 is an important pattern recognition molecule that is capable of directly killing microorganisms. the goal of this study was to identify single nucleotide polymorphis ... | 2011 | 21749417 |
| antimicrobial resistance in campylobacter, salmonella, and escherichia coli isolated from retail grain-fed veal meat from southern ontario, canada. | this study estimated the prevalence of salmonella, campylobacter, and escherichia coli isolates in fresh retail grain-fed veal obtained in ontario, canada. the prevalence and antimicrobial resistance patterns were examined for points of public health significance. veal samples (n = 528) were collected from february 2003 through may 2004. twenty-one salmonella isolates were recovered from 18 (4%) of 438 samples and underwent antimicrobial susceptibility testing. resistance to one or more antimicr ... | 2011 | 21819650 |
| synergism between ammonia and phenols for hybomitra tabanids in northern and temperate canada. | baits for tabanids (diptera: tabanidae) were tested in the northwest territories (60 °n) and ontario (45 °n) using nzi traps. tests targeted ammonia, phenols/cow urine and octenol. about 200 000 tabanids were captured in 15 experiments with a maximum capture of 4182 in one trap in 1 day. in the northwest territories, phenols, urine and octenol were effective single baits for only some species. at both locations, adding ammonia to an unbaited or an octenol-baited trap had no effect on catches. by ... | 2011 | 22150639 |
| changes in management practices and apparent prevalence on canadian dairy farms participating in a voluntary risk assessment-based johne's disease control program. | the objectives of this study were (1) to describe the change in mycobacterium avium ssp. paratuberculosis (map) antibody milk elisa-positive prevalence in canadian dairy herds that participated in a risk assessment (ra)-based johne's disease (jd) control program; (2) to describe the distribution of so-called high-risk management practices on canadian dairy farms; and (3) to assess if compliance with selected recommendations translated into changes in the scores of associated ra questions. in ont ... | 2011 | 21943773 |
| antimicrobial resistance in escherichia coli isolated from retail milk-fed veal meat from southern ontario, canada. | this study estimated the prevalence of escherichia coli isolates in fresh retail milk-fed veal scallopini pieces obtained from grocery stores in ontario, canada. in addition, the prevalence and antimicrobial resistance patterns were examined for points of public health significance. one hundred fifty-three milk-fed veal samples were collected over the course of two sampling phases, january to may 2004 and november 2004 to january 2005. e. coli isolates were recovered from 87% (95% confidence int ... | 2011 | 21819661 |
| antimicrobial susceptibility of clostridium perfringens isolates of bovine, chicken, porcine, and turkey origin from ontario. | antimicrobial susceptibilities and toxin types were determined for 275 clostridium perfringens isolates collected in ontario in the spring of 2005. minimal inhibitory concentrations (mics) of c. perfringens isolates for 12 antimicrobials used in therapy, prophylaxis, and/or growth promotion of cattle (n = 40), swine (n = 75), turkeys (n = 50), and chickens (n = 100) were determined using the microbroth dilution method. statistical analyses and mic distributions showed reduced susceptibility to b ... | 2011 | 21731178 |
| associations among pathogenic bacteria, parasites, and environmental and land use factors in multiple mixed-use watersheds. | over a five year period (2004-08), 1171 surface water samples were collected from up to 24 sampling locations representing a wide range of stream orders, in a river basin in eastern ontario, canada. water was analyzed for cryptosporidium oocysts and giardia cyst densities, the presence of salmonella enterica subspecies enterica, campylobacter spp., listeria monocytogenes, and escherichia coli o157:h7. the study objective was to explore associations among pathogen densities/occurrence and objecti ... | 2011 | 21889781 |
| impact of isoflupredone acetate treatment on clinical signs and weight gain in weanling heifers with experimentally induced mannheimia haemolytica bronchopneumonia. | objective-to characterize the impact of mannheimia haemolytica infection on feed intake and weight gain in feedlot heifers and to evaluate the clinical efficacy of isoflupredone acetate administered in combination with oxytetracycline. animals-96 weanling heifers in a research feedlot facility. procedures-bronchopneumonia was induced by intrabronchial infusion of m haemolytica. control heifers underwent a sham procedure. infected heifers were treated with oxytetracycline alone or in combinat ... | 2011 | 22126689 |
| the potential for zoonotic transmission of giardia duodenalis and cryptosporidium spp. from beef and dairy cattle in ontario, canada. | the objective of this study was to compare the occurrence and the genotypes and species of giardia duodenalis and cryptosporidium spp. in beef and dairy cattle from farms in the regional municipality of waterloo, ontario, in an effort to determine the potential for zoonotic transmission from these animals. pooled manure samples were collected from 45 dairy cattle farms and 30 beef cattle farms. the presence of giardia cysts and cryptosporidium oocysts was determined by immunofluorescence microsc ... | 2010 | 20971563 |
| ammonia emissions from livestock industries in canada: feasibility of abatement strategies. | an updated national ammonia (nh(3)) emissions inventory was employed to study the relationship between nh(3) emissions and livestock industries in canada. emissions from animal agriculture accounted for 322kilotonnes (kt) or 64% of canadian nh(3) emissions in 2002. cattle and swine accounted for the bulk of livestock emissions. the provinces of alberta, ontario, quebec, and saskatchewan accounted for 28.1%, 22.0%, 18.7%, and 13.1% of total livestock emissions, respectively. emissions from ontari ... | 2010 | 20542610 |
| assessing pest control using changes in instantaneous rate of population increase: treated targets and stable fly populations case study. | the instantaneous rate of population increase was used to assess the ability of attractive targets coated with permethrin to control stable fly populations on 3 dairy farms in south central ontario, canada. two attractive targets were deployed over 10 wk in 2001 at each of 6 dairy farms. three farms were outfitted with 2 untreated targets and 3 were outfitted with 2 targets treated with permethrin [ectiban-impregnated coroplast (ectiban: schering-plough canada inc., pointe-claire, québec, canada ... | 2010 | 20494159 |
| attitudes of canadian dairy farmers toward a voluntary johne's disease control program. | the success of johne's disease (jd) control programs based on risk assessment (ra) depends on producers' compliance with suggested management practices. one objective of this study was to describe the perception of participating canadian dairy farmers of the impact of jd, the ra process, and suggested management strategies. the second objective was to describe the cost of changes in management practices following the ra. a telephone survey was conducted with 238 dairy farmers in ontario, manitob ... | 2010 | 20338426 |
| functional comparison of hemoglobin purified by different methods and their biophysical implications. | hemoglobin (hb) that is purified from red blood cells (rbcs) is commonly subjected to harsh processing conditions, such as high temperatures and extensive column separation, which may damage the hb by altering the heme prosthetic group and/or the hb protein structure. in this study, bovine and human hb purified by tangential flow filtration (tff) was compared to commercial preparations of human hb (hemosol, inc., toronto, canada) and bovine hb (biopure, inc., cambridge, ma). purified hbs were ch ... | 2010 | 20073089 |
| factors associated with whole carcass condemnation rates in provincially-inspected abattoirs in ontario 2001-2007: implications for food animal syndromic surveillance. | ontario provincial abattoirs have the potential to be important sources of syndromic surveillance data for emerging diseases of concern to animal health, public health and food safety. the objectives of this study were to: (1) describe provincially inspected abattoirs processing cattle in ontario in terms of the number of abattoirs, the number of weeks abattoirs process cattle, geographical distribution, types of whole carcass condemnations reported, and the distance animals are shipped for slau ... | 2010 | 20704738 |
| temporal changes in the prevalence and shedding patterns of giardia duodenalis cysts and cryptosporidium spp. oocysts in a herd of dairy calves in ontario. | giardia duodenalis and cryptosporidium spp. infections, and the patterns of cyst and oocyst shedding, were observed in a herd of dairy calves in ontario over a period of 3 mo. cysts and oocysts were detected and enumerated in fecal samples using immunofluorescence microscopy; giardia and cryptosporidium dna was detected using the polymerase chain reaction. the prevalence of g. duodenalis increased during the course of the study, reaching a peak of 93.1% when calves were 43 to 54 d old, and then ... | 2010 | 21037883 |
| veterinarians' perspective on a voluntary johne's disease prevention program in ontario and western canada. | a survey was conducted to assess the beliefs of veterinarians on johne's disease (jd) and their attitudes towards the canadian, risk assessment based, jd prevention program. the veterinarians surveyed believed mycobacterium avium subsp. paratuberculosis may have zoonotic potential, liked the risk assessment based program, and thought it could lead to the prevention of other on-farm diseases. | 2010 | 20592831 |
| an analysis of the movement of dairy cattle through 2 large livestock markets in the province of ontario, canada. | data pertaining to the movement of dairy cattle through 2 large livestock markets in the province of ontario were collected for 1 week per month throughout 2004. counts and postal codes of sellers and buyers of adult dairy cattle, veal calves, and dairy calves were obtained. three assumptions were made to represent the level of mixing among animals that could take place at the markets. we estimated the number of livestock holdings that could be exposed to a highly contagious disease agent, shoul ... | 2010 | 21286326 |
| the association between foot lesions and culling risk in ontario holstein cows. | the objective was to determine the association between specific foot lesions and culling in dairy cows. using 5 trained professional hoof trimmers, data from 6,513 cows in 157 herds were recorded for analysis. during the study period, 1,293 cows (19.9%) were culled. infectious lesions were most frequent in nonculled cows, whereas hoof horn lesions were most common in the culled cows. median time to culling was 188 d [95% confidence interval (ci): 175-198 d] for cows without a lesion and 157 d (c ... | 2009 | 19447989 |
| local infestation or long-distance migration? the seasonal recolonization of dairy farms by stomoxys calcitrans (diptera: muscidae) in south central ontario, canada. | stable fly (diptera: muscidae) populations in south central ontario, canada, first occur on dairy farms in late spring, grow exponentially throughout the summer, and are frozen back each autumn. we examined the extent of overwinter persistence on 22 dairy farms in a 55- by 60-km region north of lake ontario that spans four climatic zones. our overwintering sampling of larval habitat identified three farms located in the southern section of the study region as potential overwintering refugia. usi ... | 2009 | 19449662 |
| genetic parameters of milking frequency and milk production traits in canadian holsteins milked by an automated milking system. | twice-a-day milking is currently the most frequently used milking schedule in canadian dairy cattle. however, with an automated milking system (ams), dairy cows can be milked more frequently. the objective of this study was to estimate genetic parameters for milking frequency and for production traits of cows milked within an ams. data were 141,927 daily records of 953 primiparous holstein cows from 14 farms in ontario and quebec. most cows visited the ams 2 (46%) or 3 (37%) times a day. a 2-tra ... | 2009 | 19528620 |
| herd-level risk factors for seven different foot lesions in ontario holstein cattle housed in tie stalls or free stalls. | worldwide, there is considerable between-herd variation within individual foot lesion prevalence studies. this variation suggests that herd-level risk factors are important from a prevention perspective. the objective was to determine the effect of selected risk factors on the prevalence of 7 foot lesions in both tie-stall and free-stall housing systems. as part of a cross-sectional foot lesion study 5 hoof trimmers recorded lesions for all cows that were foot trimmed in a herd. in addition, the ... | 2009 | 19307621 |
| challenges and opportunities for managing respiratory disease in dairy calves. | bovine respiratory disease (brd) is important for the ontario dairy industry due to the large economic and welfare costs of this disease. practical science-based management techniques are needed to control and reduce the risk of this disease. currently, the emphasis on brd is focused on early detection of disease and prevention. these areas are important but it is not practical to assume this disease will be eliminated in the near future. it is necessary to determine the best practices for carin ... | 2009 | 20003645 |
| risk factors associated with escherichia coli o157:h7 in ontario beef cow-calf operations. | the aim of this study was to identify farm management factors associated with the prevalence of escherichia coli o157:h7 among cattle in ontario beef cow-calf operations. a total of 119 cow-calf operations with more than 50 cows in southern ontario were visited between june and december 2002. from each farm, 65 fresh fecal samples were collected and cultured for e. coli o157:h7. colonies of e. coli o157:h7 were isolated using immunomagnetic separation and standard microbiological techniques. fin ... | 2009 | 19692131 |
| surviving bovine spongiform encephalopathy (bse): farm women's discussion of the effects of bse on food provisioning practices. | the economic vulnerability of beef and other farm families following the bovine spongiform encephalopathy (bse) crisis in canada poses a risk to their household food provisioning practices. the purpose of this study was to examine the effects of bse since 2003 on the food provisioning practices of beef and other farm families in three canadian provinces. semi-structured, face-to-face, in-depth interviews were conducted with 22 farm women (6 in alberta, 6 in ontario, and 10 in nova scotia) that f ... | 2009 | 19697243 |
| bovine tuberculosis in canadian wildlife: an updated history. | mycobacterium bovis infection in wild animals attracted little attention in canada until the disease was almost eliminated from domestic livestock. tuberculosis was endemic in plains bison and occurred in elk, moose, and mule deer in buffalo national park (bnp), alberta during the 1920s and 1930s. bison were moved from bnp to wood buffalo national park (wbnp), where tuberculosis became, and remains, endemic in bison, posing a risk to efforts to restore bison in northern canada. tuberculosis was ... | 2009 | 20119541 |
| bovine immunophysiology and genetics: a review of the research and career of jeanne l. burton. | 2009 | 19059653 | |
| research and teaching of dairy cattle well being: finding synergy between ethology and epidemiology. | epidemiology is a tool used to identify and quantify risk factors that contribute to the state of health or disease. in addition, the maintenance of health and recognition of nonhuman animal welfare are both key principles of health management. animal welfare and ethology provide important contributions to our ability to understand and improve health. as such, there can be a strong connection between the disciplines of ethology and epidemiology. this connection becomes a synergy through collabor ... | 2009 | 19319715 |
| comparing network analysis measures to determine potential epidemic size of highly contagious exotic diseases in fragmented monthly networks of dairy cattle movements in ontario, canada. | adult milking cow movements occurring in monthly periods in 2004-2006 were analysed to compare three network analysis measures to determine the lower and upper bounds of potential maximal epidemic size in an unrestrained epidemic: the out-degree, the infection chain or output domain of a farm, and the size of the strong and weak components. the directed networks generated by the movements of adult milking cows were highly fragmented. when all the farms that were not involved in shipments were in ... | 2008 | 18840200 |
| occurrence of campylobacter spp. in raw and ready-to-eat foods and in a canadian food service operation. | the occurrence of campylobacter spp. in a variety of foods from ottawa, ontario, canada, and raw milk samples from across canada was determined over a 2-year period. the samples consisted of 55 raw foods (chicken, pork, and beef), 126 raw milk samples from raw milk cheese manufacturers, and 135 ready-to-eat foods (meat products, salads, and raw milk cheeses). campylobacter jejuni was detected in 4 of the 316 samples analyzed: 1 raw beef liver sample and 3 raw chicken samples. an isolation rate o ... | 2008 | 18939758 |
| genotypic characterization and prevalence of virulence factors among canadian escherichia coli o157:h7 strains. | in this study, the association between genotypic and selected phenotypic characteristics was examined in a collection of canadian escherichia coli o157:h7 strains isolated from humans and cattle in the provinces of alberta, ontario, saskatchewan, and quebec. in a subset of 69 strains selected on the basis of specific phage types (pts), a strong correlation between the lineage-specific polymorphism assay (lspa6) genotype and pt was observed with all strains of pts 4, 14, 21, 31, 33, and 87 belong ... | 2008 | 18487402 |
| antimicrobial resistance in generic fecal escherichia coli from 29 beef farms in ontario. | the occurrence of antimicrobial resistance in generic escherichia coli can serve as an indicator of the pool of resistance genes potentially available for transfer to pathogenic organisms. this study was conducted on 29 volunteer beef farms in ontario to describe the prevalence and patterns of antimicrobial resistance in e. coli, and to describe changes in the prevalence of resistance during the feedlot stage of production. from the pooled fecal samples on 28 of the 29 farms, 31% of isolates fro ... | 2008 | 18505200 |
| era vaccine-derived cases of rabies in wildlife and domestic animals in ontario, canada, 1989-2004. | a vaccination program for the control of terrestrial rabies in the province of ontario, canada, began in 1989. during the period between 1989 and 2004, over 13 million baits containing the live, attenuated rabies virus era-bhk21 were distributed across the province, with the aim of immunizing foxes by the oral route. animals recovered from bait distribution areas were assayed by fluorescent antibody test for rabies virus infection. immunoreactivity with a panel of monoclonal antibodies that disc ... | 2008 | 18263823 |
| association between management practices and within-herd prevalence of cryptosporidium parvum shedding on dairy farms in southern ontario. | to identify management practices associated with an increased within-herd prevalence of cryptosporidium parvum shedding on dairy farms in southern ontario, fecal samples were taken from 1089 calves aged 7-28 days, from 119 herds. information on management practices was obtained by administering a questionnaire compiled using a modified delphi technique. data were analyzed using univariable and multivariable negative binomial regression. overall, 30% of the calves in the study were shedding c. pa ... | 2008 | 17481752 |
| herd- and cow-level prevalence of foot lesions in ontario dairy cattle. | the objectives of this cross-sectional study were to determine herd-level and cow-level prevalence estimates for 11 foot lesions in ontario dairy cattle. foot lesions were recorded by 5 hoof trimmers on 13,530 cows in 204 ontario dairy herds from march 2004 to may 2005. significant differences existed between free-stall and tie-stall housing. in free-stall housing systems, 46.4% of cows had a foot lesion, compared with 25.7% of cows in tie-stall barns. digital dermatitis was the most common lesi ... | 2008 | 18832211 |
| fatty acid profile of canadian dairy products with special attention to the trans-octadecenoic acid and conjugated linoleic acid isomers. | current scientific evidence indicates that consumption of industrial trans fatty acids (tfa) produced via partial hydrogenation of vegetable oils increases the risk of coronary heart disease. however, some studies have suggested that ruminant tfa, especially vaccenic acid (va or 11t-18:1) and rumenic acid (ra or 9c,11t-18:2), which is a conjugated linoleic acid (cla) isomer, may have potential beneficial health effects for humans. to date, no concerted effort has been made to provide detailed is ... | 2008 | 18727541 |
| prevalence and characterization of verotoxin-producing escherichia coli (vtec) in cattle from an ontario abattoir. | this study determined the prevalence of verotoxin (vt)-producing escherichia coli (vtec) in ontario beef cattle at slaughter and characterized the isolates by serotype, virulence factors, virulence markers, and antimicrobial resistance. cultures of rectal feces from 500 animals were screened for vt by an enzyme-linked immunosorbent assay (elisa) and by polymerase chain reaction (pcr) for genes vt1, vt2, and eae. the vt-elisa-positive samples were tested by a vt-immunoblot to isolate vtec colonie ... | 2008 | 18783017 |
| antimicrobial use on 24 beef farms in ontario. | understanding risk factors for antimicrobial resistance requires knowledge of antimicrobial selection pressure. the objectives of this research were to develop methodology for collecting quantitative antimicrobial use information from beef producers in ontario, to document the types and quantities of antimicrobials reported (for a minimum of 12 mo), and to compare 2 metrics for injectable use reporting. twenty-four volunteer beef producers were asked to complete a questionnaire, document drug us ... | 2008 | 18505199 |
| passive immunity in ontario dairy calves and investigation of its association with calf management practices. | adequate passive transfer of maternal immunoglobulin is important for optimal health and performance in newborn dairy calves. from june to october 2003 and january to april 2004, blood samples were collected from 961 dairy calves 0 to 8 d of age on 11 farms in southwestern ontario. this was followed by a second study conducted from may to october 2004, in which similar samples were taken from 422 calves up to 8 d of age on 119 dairy farms throughout southern ontario. for each sample collected, s ... | 2008 | 18832206 |
| phosphorus utilization and environmental and economic implications of reducing phosphorus pollution from ontario dairy cows. | a major source of environmental pollution has been overfeeding p to dairy cows, caused by the "safety margins" added to diets in order not to compromise the health and production of animals. an extant whole-animal model was evaluated using an experiment conducted in ontario to assess its applicability for predicting p excretion. the objective of the study was to use the model to estimate p excretion levels and the economic and environmental implications of implementing mitigating options by foll ... | 2008 | 18096946 |
| temperate bacteriophages affect pulsed-field gel electrophoresis patterns of campylobacter jejuni. | the recently sequenced genome of campylobacter jejuni rm1221 revealed the presence of three integrated bacteriophage-like elements. in this study, genes from the first element, a mu-like bacteriophage, were amplified by pcr and used to probe pulsed-field gels of clinical c. jejuni strains obtained from a waterborne outbreak (ontario, canada, 2000). these highly similar strains differed only by their pulsed-field gel electrophoresis (pfge) patterns due to an apparent insertion or deletion of a 40 ... | 2007 | 17135440 |
| prevalence and risk factors for postpartum anovulatory condition in dairy cows. | the objectives of this research were to determine the prevalence of the anovulatory condition within a temperate region of north america and identify cow-level and herd-level risk factors for this condition. a total of 1,341 cows from 18 herds were classified as cycling or anovular based on skim milk progesterone concentration determined at 46 and 60 +/- 7 d in milk. calving history, periparturient disease incidence, body condition score, milk ketone concentration in the first 2 wk of lactation, ... | 2007 | 17183099 |
| molecular diversity of methanogens in feedlot cattle from ontario and prince edward island, canada. | the molecular diversity of rumen methanogens in feedlot cattle and the composition of the methanogen populations in these animals from two geographic locations were investigated using 16s rrna gene libraries prepared from pooled pcr products from 10 animals in ontario (127 clones) and 10 animals from prince edward island (114 clones). a total of 241 clones were examined, with methanobrevibacter ruminantium accounting for more than one-third (85 clones) of the clones identified. from these 241 cl ... | 2007 | 17483285 |
| calf-level risk factors for neonatal diarrhea and shedding of cryptosporidium parvum in ontario dairy calves. | this work was conducted to investigate calf-level factors that influence the risk of neonatal diarrhea and shedding of cryptosporidium parvum oocysts in calves, on dairy farms in ontario with histories of calf diarrhea or cryptosporidiosis. fecal samples were collected weekly for 4 weeks from each of 1045 calves under 30 days of age on 11 dairy farms in south-western ontario during the summer of 2003 and the winter of 2004. a questionnaire designed to gather information on calf-level management ... | 2007 | 17602767 |
| beef herd poisoning due to ingestion of tansy ragwort in southwestern ontario. | deaths attributed to senecio jacobaea were investigated. the animal presented was a mature bull that was lethargic and dragging its feet. the bull was euthanized and 3 other cows died. significantly, this disease has not been documented in ontario before, and clinical signs of icterus or hepatoencephalopathy were not observed. | 2007 | 17824160 |
| prevalence and molecular characterization of giardia duodenalis and cryptosporidium spp. in dairy cattle in ontario, canada. | giardia duodenalis and cryptosporidium spp. are intestinal protozoan parasites that infect a wide range of host species, including humans. molecular characterization of these parasites has demonstrated that a number of genotypes and species are common to both humans and animals, and that zoonotic transmission may occur. numerous studies have reported a high prevalence of g. duodenalis and cryptosporidium spp. in cattle, particularly calves, and these animals are frequently associated with zoonot ... | 2007 | 17964724 |
| an investigation into the practices of dairy producers and veterinarians in dehorning dairy calves in ontario. | the objective of this survey was to describe the current state of dehorning practices by dairy producers and veterinarians in ontario and to identify opportunities to improve on existing practices. two hundred and seven producers and 65 veterinarians completed a survey on dehorning practices during the summer of 2004. seventy-eight percent of dairy producers dehorn their own calves; 22% use local anesthetics. veterinarians dehorn calves for 31% of dairy clients; 92% use local anesthetics. pain m ... | 2007 | 18189045 |
| tsetse and other biting fly responses to nzi traps baited with octenol, phenols and acetone. | octenol (1-octen-3-ol), acetone, 4-methylphenol, 3-n-propylphenol, and other potential attractants (human urine, stable fly faeces), as well as guiacol, creosol (potential repellents), were tested as baits for biting flies in north america using standard phthalogen blue if3gm cotton nzi traps, or similar commercial polyester traps. baits were tested during the summers of 2001-04 at a residence in canada and during january-august 2001 at a dairy in the u.s.a. behaviour in the presence of octenol ... | 2007 | 17373949 |
| tracking host sources of cryptosporidium spp. in raw water for improved health risk assessment. | recent molecular evidence suggests that different species and/or genotypes of cryptosporidium display strong host specificity, altering our perceptions regarding the zoonotic potential of this parasite. molecular forensic profiling of the small-subunit rrna gene from oocysts enumerated on microscope slides by u.s. environmental protection agency method 1623 was used to identify the range and prevalence of cryptosporidium species and genotypes in the south nation watershed in ontario, canada. fou ... | 2007 | 17483276 |
| update on parathyroid hormone: new tests and new challenges for external quality assessment. | it is now 43 years since berson and yalow published the first radio-immunoassay (ria) for parathyroid hormone (pth) [s.a. berson, r.s. yalow, g.d. aurbach, j.t. potts, immunoassay of bovine and human parathyroid hormone. proc natl acad sci u s a 49 (1963) 613-617] [1]. since then, there have been marked advances in our understanding of this peptide hormone, its mechanism of action and biological regulation [j.t. potts, parathyroid hormone: past and present. j. endocrinol. 187 (2005) 311-325] [2] ... | 2007 | 17493603 |
| evaluation of the dairy comp 305 module "cow value" in two ontario dairy herds. | the study was conducted to evaluate how the "cow value" module of dairy comp 305 (valley agricultural software, tulare, ca) performed under commercial conditions. the "cow value" module, cowval, computes a farm-specific net present value relative to an average replacement heifer for each cow in the milking and dry herd, which allows a ranking of the cows on the farm compared with replacing her with a typical replacement heifer on that farm. the average replacement heifer is used as the baseline ... | 2007 | 18024773 |
| a total merit selection index for ontario organic dairy farmers. | organic standards require changes in management practices so that health, fertility, and overall fitness are more important than on conventional dairy farms and require different selection objectives. a survey involving 18 (40%) ontario organic dairy farms was carried out to collect data on their production systems, breeding policies, and concerns. compared with conventional farms, organic farms had lower milk production, lower replacement rate, higher somatic cell count, and a much higher rate ... | 2007 | 17297132 |
| the effect of a progesterone releasing intravaginal device (prid) on pregnancy risk to fixed-time insemination following diagnosis of non-pregnancy in dairy cows. | the objective was to compare the probability of pregnancy after fixed-time insemination in cows diagnosed as non-pregnant and re-inseminated following the ovsynch protocol, with or without exogenous progesterone. cows (n=415) used in this study originated from 25 farms. upon diagnosis of non-pregnancy between 30 and 60 days after ai, cows were randomly assigned to receive either a progesterone releasing intravaginal device (prid; n=208) or a placebo intravaginal device (pid; n=207). all cows rec ... | 2007 | 17178146 |
| control of coagulation: a gift of canadian agriculture. | vitamin k, heparin and their antagonists remain the basis of coagulation therapies today, more than half a century after their discovery. failure of blood clotting in chicks that were fed a fat-depleted diet was observed by william mcfarlane, william graham jr. and frederick richardson of the ontario agricultural college; it led to the search that yielded vitamin k. investigation of hemorrhagic disease in cattle by francis schofield of the ontario veterinary college found an anti-thrombin substa ... | 2006 | 17330453 |
| evaluation of a contract breeding management program in selected ohio dairy herds with event-time analysis i. cox proportional hazards models. | an observational study was conducted in order to assess the impact of a contract breeding program on the reproductive performance in a selected group of ohio dairies using event-time analysis. the contract breeding program was offered by a breeding co-operative and featured tail chalking and daily evaluation of cows for insemination by co-operative technicians. dairy employees no longer handled estrus detection activities. between early 2002 and mid-2004, test-day records related to production a ... | 2006 | 16887223 |
| efficacy of monensin sodium for the reduction of fecal shedding of mycobacterium avium subsp. paratuberculosis in infected dairy cattle. | reducing the quantity of mycobacterium avium subsp. paratuberculosis (map) being shed by cows with johne's disease should decrease the risk of spread of this disease to young stock. previous work has suggested that monensin sodium decreases the pathologic lesions associated with johne's disease, but the impact on shedding of viable map remains unknown. after serologic screening of 32 dairy herds in southwestern ontario, 228 cows from 13 of these herds were enrolled into a randomized clinical tri ... | 2006 | 16631972 |
| monensin might protect ontario, canada dairy cows from paratuberculosis milk-elisa positivity. | our objective was to define the role of monensin sodium in protecting cows from being milk-elisa positive for paratuberculosis in ontario, canada dairy herds. in total, 4933 dairy cows from 94 herds were enrolled in this cross-sectional study. forty-four of the enrolled herds were selected purposively by their herd veterinarian and another 50 herds were randomly selected from a local milk production-recording agency. a herd-management survey was completed on each farm during the months of may th ... | 2006 | 16787675 |
| the relationship between herd level disease incidence and a return over feed index in ontario dairy herds. | the objective of the current research was to examine the association of herd level disease incidence with the return over feed (rof) (milk income minus feed cost) herd profit index offered through canwest dairy herd improvement. the lactational incidence risks (lir) for displaced abomasum, retained placenta, clinical mastitis, milk fever, clinical ketosis, and lameness submitted by producers (n = 48) were similar to previous reports. however, there was no negative association of clinical disease ... | 2006 | 16933554 |
| antibiotic resistance of campylobacter jejuni and campylobacter coli isolated from hog, beef, and chicken carcass samples from provincially inspected abattoirs in ontario. | campylobacterjejuni is one of the most common causes of bacterial foodborne infection in the united states, and there are reports of resistance of campylobacter spp. to antimicrobial agents used for the treatment of gastroenteritis. the purpose of this study was to determine the antimicrobial resistance patterns of campylobacter spp. isolated from hog, beef, and chicken carcasses from provincially inspected abattoirs in ontario. the agar dilution method was performed to measure antimicrobial res ... | 2006 | 16416896 |
| genotype and subtype analyses of cryptosporidium isolates from dairy calves and humans in ontario. | to assess the importance of dairy cattle as a source of human cryptosporidium infections in ontario, canada, 44 cryptosporidium isolates from neonatal dairy calves and 11 from sporadic human cases of cryptosporidiosis in the province were genotyped by pcr-rflp analyses of the cryptosporidium oocyst wall protein (cowp) and 18s rrna genes. isolates were also subtyped by sequence analysis of the 60-kda glycoprotein (gp60) gene. all bovine isolates successfully subtyped belonged to cryptosporidium p ... | 2006 | 16565813 |
| diseases and pathogens associated with mortality in ontario beef feedlots. | this study determined the prevalence of diseases and pathogens associated with mortality or severe morbidity in 72 ontario beef feedlots in calves that died or were euthanized within 60 days after arrival. routine pathologic and microbiologic investigations, as well as immunohistochemical staining for detection of bovine viral diarrhea virus (bvdv) antigen, were performed on 99 calves that died or were euthanized within 60 days after arrival. major disease conditions identified included fibrinos ... | 2006 | 16566254 |
| iron deficiency and anemia prevalence and associated etiologic risk factors in first nations and inuit communities in northern ontario and nunavut. | anemia is common among children in aboriginal communities in canada. the objectives of this study were to determine the prevalence of anemia and to identify its associated risk factors among young children in aboriginal communities in northern ontario and nunavut. | 2005 | 16625803 |
| the prevalence of milk and serum antibodies to mycobacterium avium subspecies paratuberculosis in dairy herds in ontario. | this study randomly surveyed 50 dairy herds in ontario; 18% and 30% of herds had 2 or more milk or serum enzyme-linked immunosorbent assay (elisa)-positive cows, respectively. the apparent cow level prevalence was 1.7% and 2.6% on the milk and serum elisa, respectively. the serum and milk assays agreed moderately. | 2005 | 16422065 |
| stall dimensions and the prevalence of lameness, injury, and cleanliness on 317 tie-stall dairy farms in ontario. | the study objectives were to provide a province-wide description of stall dimensions and the aspects of cattle welfare linked to stall design in the tie-stall industry. data on stall design; stall dimensions; and the prevalence of lameness, injury, and hind limb and udder cleanliness in lactating dairy cattle were collected from a sample of 317 tie-stall farms across ontario. the majority of the study farms (90%) had stalls with dimensions (length, width, tie-chain length, and tie rail height) t ... | 2005 | 16454382 |
| bovine viral diarrhea virus in alpaca: abortion and persistent infection. | an alpaca herd in eastern ontario experienced vague signs of illness, including anorexia and lethargy in 9 animals, 2.5 months after the addition of a chronically ill cria and his dam to the farm. subsequently 2 alpaca had early pregnancy loss; one aborted at 5.5 months gestation and the other at 7 months gestation. seventeen were found to have serum antibody to bovine viral diarrhea virus (bvdv), with highest titers to bvdv type 1. the fetus that was aborted at 5.5 months gestation, 3 months af ... | 2005 | 16475521 |
| prevalence of giardia and cryptosporidium in beef cows in southern ontario and in beef calves in southern british columbia. | in 1998 and 1999, fecal samples were collected from 669 beef cows on 39 farms located within 10 counties of ontario. overall prevalences of giardia, cryptosporidium muris, and cryptosporidium parvum in cows were 8.7%, 10.6%, and 18.4%, respectively. of the 39 farms sampled, giardia was detected on 64%, cr. muris on 72%, and cr. parvum on 90%. cryptosporidium parvum was detected in 28% of the cows in 1998 and in 5.2% in 1999. differences between the 2 y were attributed to sampling during calving ... | 2005 | 15759828 |
| prevalence of cryptosporidium parvum infection in southwestern ontario and its association with diarrhea in neonatal dairy calves. | cryptosporidium parvum infection was detected in 203 (40.6%) of 500 ontario dairy calves aged 7 to 21 d, on a convenience sample of 51 farms with a history of calf diarrhea. within-farm prevalence ranged from 0% to 70%, and both shedding and intensity of shedding were significantly associated with diarrhea. this parasite appears to be common in ontario dairy calves and important as a cause of dairy calf scours in the province. | 2005 | 15943123 |
| tie-stall design and its relationship to lameness, injury, and cleanliness on 317 ontario dairy farms. | the objective of this study was to identify relationships between tie-stall design and selected cow-based injury, lameness, and cleanliness measurements. all lactating dairy cows (n = 17,893) from 317 ontario tie-stall dairy farms were evaluated once between march and september 2003. stall dimensions were recorded and cows were scored for neck and hock lesions, broken tails, back arch, hind claw rotation, and udder and hind limb cleanliness. neck lesions were significantly associated with tie-ra ... | 2005 | 16107410 |
| risk factors associated with neospora caninum abortion in ontario holstein dairy herds. | the objective of this epidemiological study was to identify risk factors for neospora caninum-related abortions in ontario holstein dairy herds. a total of 88 herds, consisting of 5080 cattle, and utilizing dairy herd improvement (dhi) services, were divided into three groups. case (n = 30) and first control (n = 31) herds were selected from 1998 and 1999 fetal abortion submissions to the animal health laboratory, university of guelph, that were histopathologically positive or negative, respecti ... | 2005 | 15710518 |
| estimates of genetic parameters for canadian holstein female reproduction traits. | age at first insemination, days from calving to first insemination, number of services, first-service nonreturn rate to 56 d, days from first service to conception, calving ease, stillbirth, gestation length, and calf size of canadian holstein cows were jointly analyzed in a linear multiple-trait model. traits covered a wide spectrum of aspects related to reproductive performance of dairy cows. other frequently used fertility characteristics, like days open or calving intervals, could easily be ... | 2005 | 15905449 |